1. An introduction to the ROtifera
Dr Hendrik Segers
Belgian Biodiversity Platform
Royal Belgian Institute of Natural Sciences Brussels, Belgium

2. The Rotifera What are Rotifera? Eating… ….and not be eaten
Survival through time and space:
Reproduction and dispersal
Problems and opportunities
Hue University Rotifer Taxonomy workshop 6-12 March 2010

3. Phylum Rotifera Ca. 2030 species: Small (40-3500µm) worms 3 Seisonida,
461 Bdelloidea,
1566 Monogononta
Small ( µm) worms
Hue University Rotifer Taxonomy workshop 6-12 March 2010

4. Phylum Rotifera Predominantly freshwater, some marine, brackish water;
Highly abundant: 103.L-1 to 105.L-1: soda waters;
One of the main zooplankton groups
Hue University Rotifer Taxonomy workshop 6-12 March 2010

5. Phylum Rotifera
Uses:
Aquaculture: Brachionis plicatilis group for fish larvae;
Ecotoxicological assays (B. calyciflorus)
Scientific test organisms (e.g., parthenogenetic reproduction)
Ecological and environmental studies (e.g., water quality assessment) …
Hue University Rotifer Taxonomy workshop 6-12 March 2010

6. Phylum Rotifera Pelagic, littoral, interstitial; Solitary or colonial
Free-living or sessile
Epizoic, parasitic;
limnoterrestrial
Hue University Rotifer Taxonomy workshop 6-12 March 2010

7. Phylum Rotifera Morphology: Body: head, trunk, foot Head: corona
Body: lorica + pseudocoelom, incl. digestive, excretory, reproductive system
Foot (no tail) with attachment glands
Hue University Rotifer Taxonomy workshop 6-12 March 2010

8. Unique Features Morphology: Reproduction Anhydrobiosis Corona ciliata;
Mastax with trophi;
Lorica;
(Eutely, syncytia, unique type of protonephridia)
Reproduction
Anhydrobiosis
Hue University Rotifer Taxonomy workshop 6-12 March 2010

9. Eating… Creation of water current by corona ciliata:
Locomotion: swimming
Feeding: filtering
Food particle processing by mastax with trophi
Hue University Rotifer Taxonomy workshop 6-12 March 2010

10. Corona Higly adaptible!
Hue University Rotifer Taxonomy workshop 6-12 March 2010

11. Mastax with trophi Differentiation of the pharynx
Mastax = Muscular organ containing
Hard elements = trophi
Hue University Rotifer Taxonomy workshop 6-12 March 2010

12. Trophi Higly adaptible! Different “types” Grinding For Grasping
As « piston »
Higly adaptible!
Different “types”
Hue University Rotifer Taxonomy workshop 6-12 March 2010

13. … and not being eaten Lorica: Intracytoplasmatic lamina
Hue University Rotifer Taxonomy workshop 6-12 March 2010

14. … and not being eaten Protection by lorica Function: Stiffness
Buoyancy
Protection:
passive
Active
Hue University Rotifer Taxonomy workshop 6-12 March 2010

15. Lorica Phenotypic plasticity: morphological adaptation to environment
Simple: cyclomorphosis
Complex: predator-induced
Hue University Rotifer Taxonomy workshop 6-12 March 2010

16. Cuticle Gelatinous glycocalyx Secreted by tegumental
glands (trunk, foot)
Function:
Protection:
Chemical (unpalatability)
Mechanical
Hue University Rotifer Taxonomy workshop 6-12 March 2010

17. Reproduction Seisonida: bisexual, sexual repoduction
Bdelloidea: exclusive asexual parthenogenesis
Monogononta: heterogony
Hue University Rotifer Taxonomy workshop 6-12 March 2010

18. Reproduction Heterogony Rapid population growth
Production of resting eggs
Hue University Rotifer Taxonomy workshop 6-12 March 2010

19. Resting "eggs" Encapsulated embryos;
Draught-resistent, hatching at specific clues;
Survival through time and space;
Highly effective dispersal stages
Hue University Rotifer Taxonomy workshop 6-12 March 2010

20. Bdelloids: anhydrobiosis
Survival through metabolic inactivity;
Draught-resistent, reversal at specific clue;
Survival through time and space;
Highly effective dispersal stages
Hue University Rotifer Taxonomy workshop 6-12 March 2010

21. Constraints for studying Rotifera…
Size…
Taxonomic impedement
Cryptic speciation
e.g., Brachionus plicatilis complex
Sampling and sample handling
Hue University Rotifer Taxonomy workshop 6-12 March 2010

22. … and opportunities: The Bdelloidea of Thailand
Ecology and diversity of sessile rotifers
Molecular and morphological approach combined:
Cryptic diversity of Rotifera
Phylogeny
Genetics of bdelloids
Hue University Rotifer Taxonomy workshop 6-12 March 2010

23. Thank you for your attention
Hue University Rotifer Taxonomy workshop 6-12 March 2010